The primary hypothesis of this project is that organophosphate and pyrethroid exposure in utero and early childhood are associated with impaired neuropsychological development in the first three years of life. Data on actual levels of OP and pyrethroid exposure in children are scant, and there are no data on developmental effects at low doses. This is a cohort study of 440 infants enrolled at birth at the Magee Women's Hospital. At birth, subjects' meconium will be analyzed for organophosphate metabolites and pyrethroids, and umbilical cord blood will be analyzed for lead. Birthweight, length and head circumference will be measured at birth, and a neonatal neurological examination conducted. Children will be followed until 3 years of age. At each epoch appropriate developmental outcomes will be measured and measurements of OP's, pyrethroids and lead obtained. The effects of OP's, pyrethroids and lead on outcome will be measured, and interaction effects of the toxicants with OP's will be modeled. Other covariates to be evaluated are mother's age, education, IQ, socioeconomic status, smoking and alcohol intake. At present reference levels for OP's are derived solely from measures of Acetylcholinesterase in peripheral rodent blood. No developmental data on humans, either adults or children, are available. This project will address severe void in present day knowledge of children's exposure to pesticides, and the effects of these agents on neurobehavioral development. [unreadable] [unreadable]